jQuery only upload last dragged files - php

Question

I followed this tutorial on how to create a DragNDrop file upload.
It basically consists of
<form id='dragform'>
<input type="file" name="file[]" id="fileC" class="inputfile" multiple />
<label for="fileC" id='dropLabel'>
</label>
</form>
where the input is hidden.
The upload is done by
var $form = $('#dragform');
.on('drop', function(e)
{
droppedFiles = e.originalEvent.dataTransfer.files;
$form.trigger('submit');
});
var $input = $('.inputfile');
$input.on( 'change', function( e )
{
$form.trigger('submit');
});
$form.on('submit', function(e)
{
var ajaxData = new FormData($form.get(0));
if (droppedFiles) {
$.each( droppedFiles, function(i, file) {
ajaxData.append( $input.attr('name'), file );
});
}
[...]
});
This means there are 2 options to upload files, either by selecting or by dropping. In both cases the files are directly uploaded with AJAX. Here comes now my problem:
If I select file1.pdf then ajaxData only contains file1.pdf. If I now drop file2.pdf and file3.pdf in the DragNDrop area, then ajaxData contains file1.pdf, file2.pdf and file3.pdf - but I only want it to contain the dragged files file2.pdf and file3.pdf, since file1.pdf has been uploaded before. If I now select file4.pdf, then ajaxData includes file2.pdf,file3.pdf and file4.pdf.
What do I need to change, so that I only get the last dragged or last selected files from my form?

Answer 1

This works now:
var ajaxData;
if (droppedFiles) {
ajaxData = new FormData();
$.each( droppedFiles, function(i, file) {
ajaxData.append( $input.attr('name'), file );
});
}
else {
ajaxData = new FormData($form.get(0));
}
droppedFiles = "";